JPH0964085A - Bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve alignment accuracy without reducing speed by using an X direction motor and a Y direction motor which have low moving resolution as a linear scale and aligning a table by permitting the error to be minimum from the four deviations of first/second stopped positions from the correct positions. SOLUTION: The resolution of the linear scales 6 and 7 in the X and Y directions is permitted to be higher than the moving resolution of motors 4 and 5 for both directions. A controller 16 permits the motors 4 and 5 for both directions to operate in order to shift a substrate 2, which is placed on a placing table 3 by previous input, to a first position directly below a first camera 15, and a bonding tool 12 to a second position directly above the second camera, the deviation of the stopped position from the correct position is detected by both linear scales each time and the X and Y directions and the rotation angle of the bonding tool 12 are modified from the four deviations so as to permit the deviation to be minimum. Thus, highly accurate alignment is achieved without reducing speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding method for bonding an electronic component to a substrate, and more particularly to a bonding method capable of reducing a positioning error between the electronic component and the substrate.

[0002]

2. Description of the Related Art Conventionally, the following methods have been known as a bonding method for bonding an electronic component to a substrate. That is, an XY table that can move in a XY direction orthogonal to each other in a horizontal plane on which a substrate is placed and the XY table are
X-direction motor for moving in the X-direction, Y-direction motor for moving the XY table in the Y-direction, and X in the X-direction.
An X-direction linear scale that detects the amount of movement of the Y table, and a Y that detects the amount of movement of the XY table in the Y direction.
Direction linear scale, a bonding tool which is arranged vertically above and below the XY table, and which can hold electronic components and can be moved up and down, and an electronic tool held by the bonding tool in conjunction with the bonding tool. A rotation angle adjusting motor for rotating the component in a horizontal plane and a fixed fixing device provided above the XY table, and XY when the XY table stops at a predetermined first position.
A first camera that shoots a substrate placed on a table from above, and an electronic component that is fixedly provided on the XY table and that is held by the bonding tool when the XY table stops at a predetermined second position. And a control device that controls the operation of each of the motors and that receives images captured by the first camera and the second camera, the control device comprising: The amount of displacement of the substrate with respect to the regular mounting position and the amount of displacement of the electronic component with respect to the regular holding position by the bonding tool are calculated based on the image input from the XY table so that the positioning error is minimized. Move the board to position the board under the electronic components held by the bonding tool, and then lower the bonding tool from that state, Bonding method so that the bonding by pressing the components on a substrate is known. It should be noted that, in addition to the above-mentioned one, conventionally, a table on which a substrate is placed is set to X.
It is also known that the bonding tool is movable in the Y direction and the table and the bonding tool are relatively moved in the XY directions while positioning the substrate and the electronic component.

[0003]

By the way, in the above-mentioned conventional method, the deviation amount of the electronic component held by the bonding tool from the regular holding position and the regular mounting position of the substrate placed on the XY table are compared. Although the shift amount is a problem, the shift amount between the actual stop position and the regular first position and second position when the XY table is stopped at the first position and the second position is not considered. Conventionally, there is a slight positional deviation between the regular first position and the second position and the stop position where the XY table actually stops, but the amount of the deviation causes the substrate to be positioned below the electronic component. It has not been utilized as a basis for calculating the error in positioning, and the conventional method has a drawback that the positioning error increases accordingly. More specifically, in the past, when the movement resolution of both motors was set to 0.5 μm, the resolution of both linear scales was also set to 0.5 μm, so that the XY table is set to the first position and the second position. If the XY table is moved once each for positioning, the XY table will be moved only twice, and the maximum is 1 μm.
As a result, the positioning error occurs. In order to reduce such a positioning error, the movement resolution of the X-direction motor and the Y-direction motor and the resolution of both linear scales may be made smaller than before. That is, for example, the movement resolution of both motors may be set to 0.1 μm, and the resolution of both linear scales may be set to 0.1 μm. However, if the movement resolution of both motors is reduced in this way,
The moving speed at the time of moving the XY table in the XY directions becomes slow, and therefore, there is a disadvantage that positioning takes time. Therefore, an object of the present invention is to improve the positioning accuracy without reducing the positioning speed.

[0004]

That is, according to the present invention, a table on which a substrate is placed and which can be moved in a horizontal direction is provided, and a table which is arranged vertically upward above the table and holds an electronic component. And a rotatable bonding tool, an X-direction motor for relatively moving the table and the bonding tool in the X-direction of the XY directions orthogonal to each other, and an XY for the table and the bonding tool orthogonal to each other. Y-direction motor for relatively moving in the Y-direction, an X-direction linear scale for detecting a relative movement amount between the table and the bonding tool in the X-direction, and a relative scale between the table and the bonding tool in the Y-direction. The Y-direction linear scale that detects the amount of movement and the voltage held by the bonding tool in conjunction with the bonding tool described above. A rotation angle adjusting motor for rotating the component in a horizontal plane, a first camera for taking an image of the substrate placed on the table from above when the table stops at a predetermined first position with respect to the bonding tool, and A second camera fixedly provided on the table for photographing the electronic parts held by the bonding tool from below when the table stops at a predetermined second position with respect to the bonding tool; And a control device to which the images captured by the first camera and the second camera are input, and the control device is based on the images input from the both cameras. Calculate the amount of displacement of the board with respect to the mounting position and the amount of displacement of the electronic component with respect to the regular holding position by the bonding tool to minimize the positioning error. Table and the bonding tool are relatively moved in the X and Y directions to position the substrate at a position below the electronic component held by the bonding tool, and the bonding tool is lowered from that state to press the electronic component to the substrate for bonding. In the bonding method as described above, an X-direction linear scale having a resolution higher than that of the X-direction motor is adopted, and a Y-direction linear scale having a resolution higher than that of the Y-direction motor is adopted. , The displacement amount of the bonding tool and the table with respect to the regular first position when the bonding tool and the table are stopped at the first position is detected by both the linear scales, and the bonding tool and the table are moved to the second position. Bonding tool for the regular second position when stopped And the amount of displacement of the table is detected by both of the linear scales, and the control device determines, based on the four types of displacements described above, that the lower part of the electronic component held by the bonding tool so that the positioning error is minimized. It is configured to position the substrate at the position.

[0005]

According to this structure, the moving resolution of the X-direction motor and the Y-direction motor is not changed as it is, and a linear scale having a small resolution is adopted. Then, based on four types of shift amounts, which have not been considered in the past, including the shift amount between the actual stop position and each regular position when the table is stopped at the first position and the second position. Then, the control device performs positioning so that the positioning error is minimized. As described above, since the movement resolutions of the X-direction motor and the Y-direction motor do not need to be changed as they are conventionally, the table and the bonding tool are moved to the X direction.
The movement speed during relative movement in the Y direction does not decrease, and since the positioning is performed based on the four types of deviation amounts, the positioning error can be made smaller than before. Therefore, highly accurate positioning can be performed without lowering the positioning speed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. In FIG. 1, reference numeral 1 is an XY table movable in the X and Y directions which are orthogonal to each other in a horizontal plane.
A mounting table 3 for mounting the substrate 2 is attached at a predetermined position on the upper surface of the XY table 1, and the XY table 1 is moved by an X-direction motor 4 composed of a servomotor to move the X-axis.
In addition to being moved in the Y-direction, it is moved in the Y-direction by the Y-direction motor 5 which is a servo motor. In this embodiment, as the X-direction motor 4 and the Y-direction motor 5, those having a movement resolution of 0.5 μm are used. The XY table 1 is provided with an X-direction linear scale 6 that detects the amount of movement when the XY table 1 is moved in the X direction, and the amount of movement when the XY table 1 is moved in the Y direction. A Y-direction linear scale 7 for detecting is provided. In this embodiment, as the X-direction linear scale 6 and the Y-direction linear scale 7, those having a moving resolution of 0.1 μm are used. That is, in this embodiment, both linear scales 6, 7 are
A moving resolution higher than the moving resolution of 5 is used.
An elevating member 8 is attached to an upper side of the XY table 1 so as to be movable up and down with respect to a fixed frame 11. A conventionally known bonding tool 12 is attached to the elevating member 8 so as to face vertically downward. The lifting member 8 is designed to be lifted and lowered in conjunction with the servo motor 13.
Therefore, by rotating the servo motor 13 in the forward and reverse directions, the bonding tool 12 attached to the elevating member 8 can be moved up and down. The moving resolution of the servo motor 13 is 0.5 μm. The bonding tool 12 can adsorb and hold the chip 14 in the horizontal state at the lower end thereof, and the substrate 2 on the mounting table 3 is bonded to the bonding tool 12.
By lowering the bonding tool 12 holding the chip 14 from the state in which the chip 14 is positioned at the lower position, the chip 14 can be pressed against the substrate 2 to be bonded.
The bonding tool 12 is also interlocked with the servo motor 9 arranged vertically downward on the upper end of its main body,
By rotating the servo motor 9 by a required angle, the lower end of the bonding tool 12 is rotated in the normal direction in the horizontal plane so that the rotational angle position of the chip 14 held at the lower end in the horizontal plane can be adjusted. Has become. A plurality of trays 10 on which a large number of chips 14 are mounted are placed on the upper surface of the XY table 1. The XY table 1 is moved in the XY direction by a required amount, and then the bonding tool 12 is moved up and down by a required amount. As a result, one chip 14 in the tray 10 is suction-held. On the other hand, the substrate 2 is placed on a predetermined position of the mounting table 3 manually or by a transfer device (not shown). A first camera 15 whose vertical direction is directed downward is fixedly provided at a predetermined position above the XY table 1. When the XY table 1 is moved and the substrate 2 on the mounting table 3 is stopped at the first position where the substrate 2 on the mounting table 3 is stopped below the first camera 15, the first camera 15 moves to the substrate 2 on the mounting table 3.
The mounting state of the substrate 2 is photographed, and the photographed image of the substrate 2 is input to the control device 16. In addition, at a predetermined position on the upper surface of the XY table 1, the second
The camera 17 is attached so as to face vertically upward. Then, the second camera 1 is placed below the bonding tool 12.
When the XY table 1 is stopped at the second position where 7 is located, the second camera 17 photographs the holding state of the chip 14 by the bonding tool 12, and the image is the control device 1
6 is input. Each motor 4,
The operations of 5, 9, 13 are controlled by the control device 16, and in the present embodiment, the control device 16 is
The substrate 2 is positioned below the chip 14 held by the bonding tool 12 as follows. That is, as shown in FIG. 1, while the substrate 2 is placed at a predetermined position on the placing table 3 and the chip 14 is suction-held on the lower end portion of the bonding tool 12, first, as shown in FIG. The controller 16 operates the X-direction motor 4 and the Y-direction motor 5 in advance to control the controller 16 in advance.
The XY table 1 is moved to the first position input in step 1 and stopped (S1). When the XY table 1 is located at the first position, the mounting table 3 is located immediately below the first camera 15.
The upper substrate 2 stops. Here, actually XY table 1
There is a slight misalignment between the stopped first position and the regular first position. In the present embodiment, this amount of displacement, which was conventionally ignored, is used as data for positioning. That is, as described above, the movement resolution of the X-direction motor 4 and the Y-direction motor 5 is 0.5 μm,
On the other hand, the resolution of the X-direction linear scale 6 and the Y-direction linear scale 7 is set to 0.1 μm.
The displacement amount in the XY directions regarding the position is detected by the linear scales 6 and 7 in units of 0.1 μm, and is input to the control device 16. Here, for example, if the displacement amount in the X direction is 0.3 μm and the displacement amount in the Y direction is 0.3 μm, the displacement amounts in the XY directions detected by both linear scales 6 and 7 are as shown in FIG. , Is input to the first storage unit 16a of the control device 16 via the counter 21,
The storage unit 16a stores the shift amount in the XY directions (S
2). Next, as described above, when the XY table 1 actually stops at the first position, the mounting condition of the substrate 2 on the mounting table 3 is photographed by the first camera 15, and the image thereof is stored in the substrate image of the control device 16. It is input to the unit 16b (FIG. 3) and stored (S3). Next, the control device 16 operates the X-direction motor 4 and the Y-direction motor 5 again to move the XY table 1 to the second position which has been input to the control device 16 in advance and stop it (S4). When the XY table 1 is located at the second position, the second camera 17 provided on the XY table 1 is located directly below the bonding tool 12. Here, there is a slight deviation between the second position where the XY table 1 actually stops and the regular second position.
In the present embodiment, this amount of displacement, which was conventionally ignored, is also used as data for positioning. Then, the deviation amount between the second position where the XY table 1 is actually stopped and the regular second position is detected by the linear scales 6 and 7 in units of 0.1 μm and input to the control device 16. Here, for example, if the amount of deviation in the X direction is 0.2 μm and the amount of deviation in the Y direction is 0.2 μm, as shown in FIG. 3, the XY directions regarding the second position detected by both linear scales 6 and 7 The amount of deviation of the
1 is input to the second storage unit 16c of the control device 16, and the second storage unit 16c stores the shift amount in the XY directions (S5). Next, as described above, when the XY table 1 actually stops at the second position, the second camera 17 provided on the XY table 1 photographs the holding state of the chip 14 held by the bonding tool 12, and the image thereof is captured. Is input to and stored in the chip image storage unit 16d of the control device 16 (S6). After this, the calculation unit 16e of the control device 16
In order to position the substrate 2 at an optimum position below the chip 14 held by the bonding tool 12, based on the four types of displacement amounts stored in the respective parts 16a to 16d, the XY direction and the rotation angle are set. The position where the error is minimized is calculated (S7). In this way, the control device 16
When the calculation unit 16e of the above obtains the position where the error in the XY direction and the rotation angle is minimized, the control device 16 controls the motors 4,
5 and 9 are operated, and X is moved to the position calculated by the calculation unit 16e.
While the Y table 1 is moved, the bonding tool 12 is rotated by the amount of deviation of the rotation angle (S8). Here, if the control device 16 determines that it is not positioned at the position calculated by the calculation unit 16e based on the movement amount of the XY table 1 detected by both the linear scales 6 and 7, the control device 16 continues to operate. The XY table 1 is moved to the position obtained by the calculation unit 16e by rotating each motor 4, 5, 9 by a required amount. As a result, the substrate 2 is arranged so that the error is minimized below the chip 14 held by the bonding tool 12.
Has been positioned (S9). When the positioning is completed as described above, thereafter, the controller 16 operates the motor 13 to operate the bonding tool 1 in the same manner as in the conventional case.
Since 2 is lowered by a predetermined amount, the chip 14 is pressed against and bonded to the substrate 2. As described above, according to the present embodiment, not only the displacement amount of the mounting position of the substrate 2 captured by the first camera 15 and the displacement amount of the holding position of the chip 14 captured by the second camera 17 Each deviation amount from the regular position when the XY table 1 is actually stopped is detected at the first position and the second position which have been ignored, and the error is minimized based on these four kinds of deviation amounts. Is positioned as follows. Therefore, X at the first position and the second position
The positioning error can be reduced and the positioning accuracy can be improved as compared with the conventional case in which the deviation amount between the actual stop position and the regular position when the Y table 1 is positioned is ignored. it can. On the other hand, since both motors 4 and 5 for moving the XY table 1 can have the same moving resolution as the conventional one, the moving speed of the XY table 1 can be improved in spite of improving the positioning accuracy. It never drops. In contrast to the present embodiment described above, conventionally, the movement resolution of both motors XY and the resolution of both linear scales 6 and 7 are made the same, and the first
When the XY table 1 is stopped at the position and the second position, the XY table 1 is treated as if it is stopped at the regular first position and the second position. Therefore, conventionally, the displacement amount of the mounting position of the substrate 2 photographed by the first camera 15 at the first position and the displacement amount of the holding position of the chip 14 photographed by the second camera 17 at the second position are calculated based on the conventional method. In addition, the control device 16 calculates the amount of movement in the XY directions required for positioning.
As described above, in the conventional case, the XY table has the normal first position and the second position when the XY table actually stops at the first position and the second position.
Since the amount of displacement with respect to the position was not taken into consideration, in the related art, the positioning error between the chip 14 and the substrate 2 in the XY directions at the time of completion of positioning was correspondingly large. (Second Embodiment) Next, FIGS. 4 to 6 show a second embodiment of the present invention. In the first embodiment, the XY table 1 itself moves in the XY directions, whereas in the second embodiment, the table 1 moves only in the Y direction, while the lifting member is moved. The frame 11 to which 8 is attached can be moved in the X direction. The frame 11 is adapted to be moved by an X-direction motor 4 ′ linked to it, and the X-direction linear scale 6 ′ is provided in the longitudinal direction of the frame 11. The other structure is the same as that of the first embodiment described above, and the same member numbers are given to the respective members corresponding to the first embodiment. In the second embodiment having such a configuration, the control device 16 positions the substrate 2 and the chip 14 as follows. That is, as shown in FIG. 4, the substrate 2 is placed at a predetermined position on the placing table 3, and the chip 14 is sucked and held on the lower end portion of the bonding tool 12, and as shown in FIG. Device 1
6 operates the X-direction motor 4 ′ and the Y-direction motor 5 to move the table 1 and the bonding tool 12 to the first position which has been input to the control device 16 in advance and stop them (S1 ′). In this way, when the table 1 and the bonding tool 12 are located at the first position, the substrate 2 on the mounting table 3 stops at a position directly below the first camera 15.
Here, the table 1 and the bonding tool 1 are actually
There is a slight deviation between the first position where 2 stops and the normal first position. Then, as shown in FIG. 6, the amount of deviation in the XY directions detected by both linear scales 6 ′ and 7 is detected by the first storage unit 1 of the control device 16 via the counter 21.
6a, and the first storage unit 16a stores the shift amount in the XY directions (S2). Next, as described above, when the table 1 and the bonding tool 12 actually stop at the first position, the mounting state of the substrate 2 on the mounting table 3 is photographed by the first camera 15, and its image is displayed by the controller 16. It is input to the board image storage unit 16b (FIG. 6) and stored (S3). Next, the control device 16 operates the X-direction motor 4 ′ and the Y-direction motor 5 again to preliminarily control the control device 16 in advance.
The table 1 and the bonding tool 12 are moved to the second position that has been input in step 1 and stopped (S4 ').
When the table 1 and the bonding tool 12 are located at the second position, the second camera 17 provided on the table 1 is located directly below the bonding tool 12. here,
There is a slight deviation between the second position where the table 1 and the bonding tool 12 actually stop and the regular second position. Then, as shown in FIG. 6, the shift amount in the XY directions regarding the second position detected by both linear scales 6 ′ and 7 is input to the second storage unit 16c of the control device 16 via the counter 21, and 2 The storage unit 16c has X
The shift amount in the Y direction is stored (S5). Next, as described above, when the table 1 and the bonding tool 12 actually stop at the second position, the second camera 17 provided on the table 1 photographs the holding state of the chip 14 held by the bonding tool 12, The image is the control device 16
Is input to and stored in the chip image storage unit 16d (S6). After that, the calculation unit 16e of the control device 16 determines the chip 14 held by the bonding tool 12 based on the four types of deviation amounts stored in the above units 16a to 16d.
In order to position the substrate 2 at the optimum position below, the position where the error in the XY direction and the rotation angle is minimized is calculated (S7 ′). In this way, when the calculation unit 16e of the control device 16 obtains the position where the error in the XY direction and the rotation angle is the minimum, the control device 16 causes the motors 4 ',
5 and 9 are operated to move the table 1 and the bonding tool 12 to the position obtained by the calculation unit 16e, and the bonding tool 12 is moved by the amount of deviation of the rotation angle.
Is rotated (S8 '). Here, when the control device 16 determines that it is not positioned at the position obtained by the calculation unit 16e based on the movement amounts of the table 1 and the bonding tool 12 detected by the linear scales 6 and 7, The motors 4 ′, 5 and 9 are continuously rotated by a required amount to move the table 1 and the bonding tool 12 to the positions obtained by the calculation unit 16e. As a result, the substrate 2 is positioned below the chip 14 held by the bonding tool 12 so as to minimize the error (S).
9). Even in the second embodiment, the first position,
Since the amount of deviation between the actual stop position and the regular stop position when the table 1 and the bonding tool 12 are moved to the second position is used as data for positioning,
Similar to the first embodiment, it is possible to perform highly accurate positioning without lowering the positioning speed. In each of the above-described embodiments, the board 2 and the chip 14 are moved by the cameras 15 and 17. Although the image is taken only once, as shown by an imaginary line in FIG. 7, it may be possible to take images at predetermined two positions on the substrate 2 and the chip 14, respectively. In this case, S2 and S3 in FIGS. 2 and 5 are repeated twice, and S5 and S6 are repeated two times.
It will be repeated times. In this way both cameras 15, 17
By taking images of two predetermined places, the positioning accuracy can be further improved.

[0007]

As described above, according to the present invention, it is possible to obtain the effect that the positioning can be performed with high accuracy without lowering the positioning speed.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing one embodiment of the present invention.

FIG. 2 is a diagram showing a work process by the control device shown in FIG.

FIG. 3 is a configuration diagram showing a relationship between the control device shown in FIG. 1 and other components.

FIG. 4 is an overall perspective view showing another embodiment of the present invention.

5 is a diagram showing a work process by the control device shown in FIG.

6 is a configuration diagram showing the relationship between the control device shown in FIG. 4 and other components.

FIG. 7 is a plan view showing different photographing positions when the substrate 2 is photographed by the first camera 15.

[Explanation of symbols]

1 XY table (table) 2 substrate 4 X direction motor 4'X direction motor 5 Y direction motor 6 X direction linear scale 6'X direction linear scale 7 Y direction linear scale 9 motor 12 bonding tool 13 motor 14 chip (electronic component) 15 first camera 16 control device 17 second camera

Claims (2)

[Claims] 1. A table on which a substrate is placed and which can be moved in the horizontal direction, and a bonding which is arranged vertically above the table and vertically downward, can hold electronic components and can be raised and lowered, and can be rotated. A tool, an X-direction motor that relatively moves the table and the bonding tool in the X direction of the XY directions that are orthogonal to each other, and a Y direction that relatively moves the table and the bonding tool in the Y direction of the XY directions that are orthogonal to each other. A motor, an X-direction linear scale that detects a relative movement amount between the table and the bonding tool in the X direction, and a Y-direction linear scale that detects a relative movement amount between the table and the bonding tool in the Y direction. , A rotation angle for rotating the electronic component held by the bonding tool in a horizontal plane in association with the bonding tool An adjusting motor and a first image of the substrate mounted on the table from above when the table is stopped at a first predetermined position with respect to the bonding tool.
A camera and a second camera fixedly provided on the table for photographing the electronic parts held by the bonding tool from below when the table stops at a predetermined second position with respect to the bonding tool. A control device that controls the operation of each of the motors and that receives the images captured by the first camera and the second camera, wherein the control device is based on the images input from both cameras. , The amount of displacement of the board with respect to the regular mounting position and the amount of displacement of the electronic component with respect to the regular holding position by the bonding tool are calculated, and the table and the bonding tool are relatively moved in the XY directions so that the positioning error is minimized. , Position the substrate at the lower position of the electronic component held by the bonding tool, and lower the bonding tool from that state, In a bonding method in which an electronic component is pressed against a substrate to be bonded, an X-direction linear scale having a resolution higher than that of the X-direction motor is adopted, and a resolution higher than that of the Y-direction motor is adopted. And a displacement amount of the bonding tool and the table with respect to the regular first position when the bonding tool and the table are stopped at the first position is detected by the both linear scales. When the bonding tool and table are stopped at the above second position, the regular second
The displacement amounts of the bonding tool and the table with respect to the position are detected by both of the linear scales, and the control device holds the bonding tool so as to minimize the positioning error based on the above-mentioned four types of displacement amounts. A bonding method characterized in that the substrate is positioned below the electronic component. 2. The image pickup device according to claim 1, wherein the first camera captures two predetermined spots on the board, and the second camera captures two predetermined spots on the electronic component. Bonding method.